Can forming machine

ABSTRACT

A can forming machine includes a can body holder in which the can body does not fall at an unexpected time. A knockout unit has a knocking out piston which is disposed to be movable in a depth direction of a recess and is provided to be displaceable between a protruding position at which the knocking out piston protrudes into the recess and an recessed position at which the knocking out piston exits the recess, and a cylinder which supports the knocking out piston to be displaceable. At a discharge position, at which the formed can body is discharged from the recess of the can body holder, a piston displacing unit, which displaces the knocking out piston from the recessed position toward the protruding position, is provided adjacent to the other surface side of the base.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application claims priority from Japanese Patent Application No.2016-106552 filed on May 27, 2016, the entire contents of which areincorporated herein by reference.

BACKGROUND Field of the Invention

The present invention relates to a holding unit of a can body in a canforming machine.

Description of Related Art

As a can body that is filled with contents such as a beverage andsealed, a bottomed cylindrical can body having a can barrel (wall) and acan bottom (bottom), and a bottle can with a thread cap screwed onto anopening end portion of the can are known. The can body of such a bottlecan is diagonally narrowed so that an upper portion is constricted, anda thread groove for screwing the thread cap is formed on the side of theopening portion.

When such a bottle can is formed, for example, a product (a can basematerial) obtained by drawing a metal plate made of aluminum or analuminum alloy into a cup shape is redrawn using the can formingmachine, and the side walls are stretched in multiple ironing steps.After adjusting the height of the can body thus obtained by trimming,printing is performed on a circumferential surface of the can body.Thereafter, a bottle can is formed through a necking process in whichthe opening end side of the can body is drawn.

In the forming of such a bottle can, the bottle necker, which is a canforming machine used in the necking process, rotates a turntable inwhich multiple can body holders for supporting the bottom side of thecan body are arranged in an annular shape. Further, in order to face therespective can body holders, opening end sides of the can body held bythe can body holder are sequentially pressed against multiple neckingtoolings arranged on the die table in a ring shape, and drawing isperformed in steps (see, for example, Japanese Unexamined PatentApplication, First Publication No. 2008-126266).

In a slide air valve unit described in Japanese Unexamined PatentApplication, First Publication No. 2008-126266, in order to supply gasfor detaching a can body to a rotating can body holder, a fixing memberincluding multiple long grooves through which gas flows is provided. Bymoving one end of a gas supply pipe extending from each of the can bodyholders along the long groove with the rotation of the can body holder,even if the can body holder rotates, it is possible to supply the gas.

Conventionally, as a unit for holding a can body in a bottle necker orthe like, for example, there is a container holder described in JapaneseUnexamined Patent Application, First Publication No. 2008-126266. Thecontainer holder includes a container holding member which expands withthe supply of air to hold the circumferential surface of the container,and a piston which pushes out the container from the holder.

The slide air valve unit disclosed in Japanese Unexamined PatentApplication, First Publication No. 2008-126266 is configured so that anair pipe which operates a container holding member for holding acontainer, and an air pipe which operates the piston for pushing out thecontainer are always connected to each other via a manifold while theholder rotates. For this reason, there was a risk of the pistonunexpectedly operating due to an erroneous operation of a valve or thelike for controlling the supply of air, and the container being pushedout and falling when the holder was not at a container extractionposition.

The present invention has been made in view of the above circumstances,and an object thereof is to provide a can forming machine in which a canbody does not fall from a can body holder at an unexpected timing.

SUMMARY OF THE INVENTION

In order to solve the above-mentioned problems, according to an aspectof the present invention, there is provided a can forming machine whichincludes a turntable in which multiple can body holders configured todetachably hold a can body are annularly arranged on one surface side(the first surface side) of a base in a disc shape, the can body holdershave a recess into which at least a bottom side of the can body can beinserted, and a knockout unit, the knockout unit has a knocking outpiston which is disposed to be movable in a depth direction of therecess and is provided to be displaceable between a protruding positionat which the knocking out piston protrudes into the recess and anrecessed position at which the knocking out piston exits the recess, anda cylinder which supports the knocking out piston to be displaceable,and at a discharge position at which the formed can body is dischargedfrom the recess of the can body holders, a piston displacing unit whichdisplaces the knocking out piston from the recessed position toward theprotruding position is provided adjacent to the other surface (thesecond surface side) side of the base.

According to the can forming machine of the present invention, since thepiston displacing unit for operating the knocking out piston is disposedat least to the position at which the can body is discharged from thecontainer holding unit, it is possible to reliably prevent an erroneousoperation in which the knocking out piston unexpectedly protrudes intothe recess during machining of the can body and causes the can bodybeing machined to fall.

An opening through which one surface side (the first surface side) andthe other surface side (the second surface side) of the base communicatewith each other may be formed in a part of the base in which the canbody holders are disposed.

The piston displacing unit may be a gas valve connected to a gaspressure adjusting unit which feeds gas into the cylinder.

The gas valve may be further disposed to one or more positions between aposition subsequent to the discharge position to the introductionposition along a rotational direction of the turntable, and may not bedisposed between the position subsequent to the introduction positionand a position previous to the discharge position.

The gas valve may be disposed to each position between the dischargeposition and an introduction position at which the can body beforeforming is introduced into the recess, and the gas pressure adjustingunit may feed gas into the cylinder via the gas valve and suction theinterior of the cylinder to displace the knocking out piston from theprotruding position toward the recessed position.

Other aspect of the present invention is a can body holder including: arecess which receives a lower portion of a can body; a can body holdingunit disposed to an inner circumferential surface side of the recess;and a knockout unit disposed to a bottom surface side of the recess,wherein the can body holding unit includes an elastic part partiallyexposed on the inner circumferential surface of the recess, and theknockout unit includes a knockout cylinder, and a knocking out pistonsupported inside the knockout cylinder to be movable in an axisdirection of the knockout cylinder.

In the can body holder of the other aspect of the present invention, theelastic part may be in a ring shape having a rectangular cross section,made of rubber, a hollow portion may be formed in the rectangular crosssection, and a first gas pressure adjusting unit configured to apply agas pressure from outside to an inside of the hollow portion may beconnected to the elastic part.

In addition, in the can body holder of the other aspect of the presentinvention, a substantially cylindrical cylinder shape may be formed inthe knockout cylinder, a pressure adjusting hole may be disposed to theknockout cylinder to release an air compressed in the knockout cylinderby movement of the knocking out piston.

According to the present invention, it is possible to provide a canforming machine in which the can body does not fall from the can bodyholder at an unexpected timing.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flowchart illustrating forming processes of a DI can instages.

FIGS. 2A-2G are schematic views illustrating a change in a shape of acan body in each process.

FIG. 3 is an external perspective view illustrating a can formingmachine (necking apparatus).

FIG. 4 is a perspective view illustrating a turntable and its vicinity.

FIG. 5 is an enlarged perspective view illustrating a main part of theturntable.

FIG. 6 is a plan view of the turntable seen from the die table side.

FIG. 7 is a partially broken perspective view illustrating aconfiguration of a can body holder.

FIG. 8 is a cross-sectional view illustrating a configuration of the canbody holder.

FIG. 9 is an enlarged perspective view of a main part when the vicinityof a can body insertion position of the turntable is viewed from theback side.

FIG. 10 is a partially broken perspective view when the vicinity of thecan body discharge position of the turntable is viewed from the frontsurface side.

FIG. 11 is a cross-sectional view illustrating the operation of a canbody holding unit.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, a can forming machine of an embodiment of the presentinvention will be described with reference to the drawings. Thefollowing respective embodiments are described in detail for betterunderstanding of the scope of the invention, and do not limit thepresent invention unless otherwise specified. In the drawings used inthe following description, for easy understanding of the features of thepresent invention, there are cases in which the main portions areenlarged for the sake of convenience, and the dimensional ratios of thecomponents are not necessarily the same as the actual case.

First, a series of flows of forming process of a bottle can, which is anexample of a can body, will be described.

FIG. 1 is a flowchart illustrating an example of a forming process of abottle can in steps. FIGS. 2A-2G are schematic views illustrating achange in the shape of the can body in each process.

The bottle can is forming via a plate material punching step S1, acupping step (drawing step) S2, a DI step (drawing and ironing step) S3,a trimming step S4, a printing and coating (can outer surface) step S5,a coating (can inner surface) step S6, and a necking step S7 in thisorder.

In the plate material punching step S1, for example, a rolled materialmade of an Al alloy material is punched to form a disk-like platematerial (blank) W as illustrated in FIG. 2A (a punching process isperformed). In the cupping step (drawing step) S2, as illustrated inFIG. 2B, the plate material W is drawn (cupped) in a cupping press andis formed into a cup-like body (can base material) W1. In the DI step(drawing and ironing step) S3, DI machining (re-drawing and ironing) isperformed on the cup-like body W1 as illustrated in FIG. 2C by the DImachining apparatus, and the can barrel 11 and the bottom 12 form anintegral bottomed cylindrical can body W2.

In the trimming step S4, since the height of the opening end portion 11a of the can body W2 is not uniform, the opening end portion lla istrimmed using a trimming device, and as illustrated in FIG. 2D, thetrimmed can body W3 in which the height of the opening end portion 11 aof the can barrel 11 is evenly aligned over the entire circumference isformed.

Thereafter, after the can body W3 is cleaned to remove the lubricatingoil and the like, the surface treatment is performed and the drying isperformed. Thereafter, as illustrated in FIG. 2E, the printing andcoating on the outer surface side llb of the can body W3 are performed(printing and coating (can outer surface) step S5), and thereafter, theinner surface side 11 c of the can body W3 is coated (coating (can innersurface) step S6).

Next, a neck portion 12 having a smoothly inclined narrowed shape isformed (necking step S7) on the opening end portion 11 a side of the canbarrel 11 using a necking tooling. Further, a thread groove 13 (see FIG.2G) matching the shape of the cap is formed in the neck portion 12 atthe opening end portion of the neck portion 12 using a screw tool(molding tool) (a screw forming step S8). The can forming machineaccording to this embodiment is a necking apparatus used in the neckingstep S7 and the screw forming step S8. With such a necking apparatus, acan body (bottle can) 10 having a constricted neck portion 12 is formedon the opening end portion lla side of the can barrel 11 (see FIG. 2F).

Thereafter, the can body (bottle can) 10 obtained through each of thesteps described above is filled with contents such as a beverage or thelike, a cap fitted with the thread groove 13 to cover the opening of theneck portion 12 is attached, and the interior of the can body 10 issealed.

FIG. 3 is an external perspective view illustrating a can formingmachine (necking apparatus). FIG. 4 is an external perspective viewillustrating the turntable and its peripheral edge portion. Further,FIG. 5 is an enlarged perspective view illustrating a part of theturntable.

A can forming machine (necking apparatus) 20 is a can forming machineused for the necking step S7 and the screw forming step S8 describedabove, and includes a 21 having a rotary shaft (not illustrated) or areciprocating unit (not illustrated), a turntable 23 axially attached tothe rotary shaft of the main body 21, and a die table 24 disposed toface the turntable 23. Further, a sliding ring member 25 and a fixingring member 26 are disposed to the vicinity of the turntable 23 in thecentral direction.

The turntable 23 is, for example, a member in which multiple can bodyholders 31 capable of holding the bottom portion of the can body areannularly disposed on one surface side 23 a of the table main body(base) 23A having a ring-shaped flat plate. The turntable 23 isrotatably supported by an index (not illustrated) disposed to the mainbody 21, and intermittently rotates about the rotary axis. Theconfiguration of the can body holder 31 will be described later indetail.

Through air supply grooves and air supply pipes (not illustrated)disposed to each of the sliding ring member 25 and the fixing ringmember 26, the gas pressure can be applied to the can body holding unit33 (see FIG. 7) of the can body holder 31 to be described later via thesliding ring member 25 rotating with the turntable 23.

The die table 24 is, for example, a member in which multiple formingtoolings 41 are annularly arranged on one surface side 24 a facing theturntable 23 of the table main body 24A having a ring-shaped flat plate.The die table 24 is disposed to be movable along the X-axis which is theforming direction by a reciprocating unit (not illustrated). That is,the die table 24 reciprocates to narrow or widen the space between thedie table 24 and the turntable 23. Further, the turntable 23 onlyreciprocates along the X-axis without rotating.

The forming tooling 41 includes multiple forming toolings 41, 41 . . .in which the forming shapes are changed in steps in the can body holder31 of the turntable 23 such that the neck portion 12 (see FIGS. 2F, 2G)of the can body 10 is gradually formed from a position opposed to a canbody insertion position P1 (see FIG. 6), for example, at which the neckportion pushes an unformed can body, in the rotational direction(counterclockwise direction Q in FIG. 6) of the turntable 23. Further, ascrew tool (forming tooling) 61 for forming the thread groove 13 (seeFIG. 2G) may be disposed to the opening end narrowed by the neck portion12, following the forming tooling 41 at the final stage.

FIG. 6 is a plan view of the turntable when viewed from the die tableside.

The turntable 23 of the present embodiment intermittently rotates in thecounterclockwise direction Q. Further, the can body with the unformedneck portion sent from the previous step is pushed into the can bodyholder 31, which reaches the position adjacent to a star wheel 51Adisposed at the outer edge portion of the turntable 23, among themultiple annularly arranged can body holders 31, 31 . . . (the can bodyinsertion position P1).

Further, the can body 10 formed with the held neck portion 12 is pushedout from the can body holder 31 which reaches the position adjacent tothe star wheel 51B (the can body discharge position P2). A can bodyholding unit 33 or a knock-out unit 34, which will be described later,acts on the can body holder 31 located at the can body insertionposition P1 and the can body discharge position P2.

FIG. 7 is a partially cutaway perspective view illustrating an exampleof the can body holder. FIG. 8 is a cross-sectional view illustrating astate in which the can body holder is at the can body dischargeposition. Further, FIG. 9 is an enlarged perspective view of a main partwhen the vicinity of the can body insertion position of the turntable isviewed from the back side. Further, FIG. 10 is a partially brokenperspective view when the vicinity of the can body discharge position ofthe turntable is viewed from the front side.

The can body holder 31 includes, for example, a recess 32 which receivesa lower portion (a bottom portion) of the trimmed can body W3illustrated in FIG. 2D, a can body holding unit 33 disposed to the innercircumferential surface 32 a side of the recess 32, and a knockout unit34 disposed to the bottom surface 32 b side of the recess 32.

The can body holding unit 33 includes an elastic part 42 that ispartially exposed on the inner circumferential surface 32 a of therecess 32. The elastic part 42 is, for example, a ring-shaped memberhaving a rectangular cross section made of an elastic member such asrubber and having a hollow portion 42 a formed therein. In the elasticpart 42, a first gas pressure adjusting unit 43 for applying the gaspressure from the outside to the inside of the hollow portion 42 a isconnected to the sliding ring member 25 and the fixing ring member 26via the air supply pipe 35.

The first gas pressure adjusting unit 43 is made up of, for example, acompressor which applies the compressed air to the inside of the hollowportion 42 a of the elastic part 42. The operation of the first gaspressure adjusting unit 43 is controlled in accordance with the positionof the can body holder 31 disposed to the turntable 23. The opening andclosing control of the supply of the gas from the first gas pressureadjusting unit 43 to the elastic part 42 is performed by a change in therelative rotational position between the sliding ring member 25 and thefixing ring member 26.

As illustrated in FIG. 11A, in the can body holding unit 33, in a statein which the gas pressure is not applied from the first gas pressureadjusting unit 43 (see FIG. 7) to the inside of the hollow portion 42 aof the elastic part 42, the elastic part 42 maintains its originalshape. In this state, since the elastic part 42 does not protrude fromthe inner circumferential surface 32 a of the recess 32, the elasticpart 42 does not abut against the circumferential surface of the canbody W3. A state illustrated in FIG. 11A is a can body release positionat which the can body 10 introduced into the recess 32 is not locked(held) to the can body holding unit 33.

Meanwhile, as illustrated in FIG. 11B, in a state in which the gaspressure is applied from the first gas pressure adjusting unit 43 (seeFIG. 8) to the inside of the hollow portion 42 a of the elastic part 42,the gas pressure inside the hollow portion 42 a of the elastic part 42increases. As a result, a portion of the elastic part 42 exposed to theinner circumferential surface 32 a of the recess 32 protrudes (bulges)from the inner circumferential surface 32 a, and narrows the diameter ofthe inner circumferential surface 32 a of the recess 32. In this state,the protruding portion 42 b of the elastic part 42 comes into contactwith the circumferential surface of the bottom portion of the can bodyW3, and the can body W3 is held by the bulging elastic part 42. Thestate illustrated in FIG. 11B is a can body holding position at whichthe can body 10 introduced into the recess 32 is engaged (held) with thecan body holding unit 33.

The knockout unit 34 includes a knockout cylinder (cylinder) 44, and aknocking out piston 45 supported inside the knockout cylinder 44 to bemovable in the X-direction in FIG. 7. The knockout cylinder 44 has asubstantially cylindrical cylinder space S. Further, a pressureadjusting hole (gas vent hole) 58 is disposed to the knockout cylinder(cylinder) 44 to release the air compressed in the knockout cylinder 44by the movement of the knocking out piston 45. The pressure adjustinghole 58 may be, for example, a through-hole which allows the interiorand the exterior of the knockout cylinder 44 to communicate with eachother.

An opening 54 through which one surface side 23 a and the other surfaceside 23 b of the table main body (base) 23A communicate with each otheris formed at a position at which the can body holder 31 is disposed inthe table main body (base) 23A of the turntable 23. The opening 54communicates with the cylinder space S formed in the knock-out cylinder44, such that a gas pressure such as compressed air can be applied tothe inside of the cylinder space S from the other surface side 23 b ofthe table main body (base) 23A.

Further, on the other surface side 23 b of the table main body (base)23A, in a portion in which the opening 54 is formed, multiplerectangular spacer plates 55 rotating together with the turntable 23 aredisposed lined up. In each of these spacer plates 55, an opening 54 acommunicating with the opening 54 formed in the table main body (base)23A is formed.

On the other surface side 23 b of the table main body (base) 23Aconstituting the turntable 23, a disk-shaped fixed support plate 57 isfurther disposed. The fixed support plate 57 is a non-rotatable fixingmember, and for example, is disposed to the other surface side 23 b ofthe table main body (base) 23A to be rotatable with respect to the tablemain body (base) 23A via the spacer plate 55 to allow rotation of theturntable 23.

Gas valves (piston displacing units) 56, 56, . . . constituting thepiston displacing unit are disposed to the fixed support plate 57, froma part corresponding to (overlapping) the can body discharge position P2(see FIG. 6) for discharging the formed can body 10 from the can bodyholder 31, to a part corresponding to (overlapping) the positioncorresponding to (overlapping) the can body insertion position P1 (seeFIG. 6) along the rotational direction Q of the turntable 23. In thepresent embodiment, the gas valves (piston displacing units) 56, 56 . .. are disposed to each of positions corresponding to (overlapping) threepositions of the can body discharge position P2, the can body insertionposition P1, and the position therebetween in the fixed support plate 57(see FIG. 9).

Meanwhile, the gas valve (piston displacing unit) 56 is disposed betweenthe position subsequent to the can body insertion position P1 (see FIG.6) along the rotational direction Q of the turntable 23 and the frontposition of the can body discharge position P2. That is, the gas valve(piston displacing unit) 56 is not disposed to a position facing theposition at which the forming tooling 41 and the screw tool 61 aredisposed on the die table 24 (the position facing the position at whichthe forming tooling 41 and the screw tool 61 are disposed on the dietable 24 is free of the gas valve (piston displacing unit)).

The gas valve (piston displacing unit) 56 includes a valve main body 61,a connecting pipe 62 disposed to one end side of the valve main body 61,an inner body 64, and a mounting member 65.

The inner body 64 is supported inside the valve main body 61, and apressure inner tube 63 is disposed thereto. One end side of the pressureinner tube 63 is connected to the connecting pipe 62, and the other endside thereof is exposed as an opening end in the opening 54 formed inthe fixed support plate 57. The mounting member 65 locks the gas valve(piston displacing unit) 56 at a position which overlaps the opening 54formed in the fixed support plate 57.

The connecting pipe 62 of the gas valve (piston displacing unit) 56communicates with the second gas pressure adjusting unit (gas pressureadjusting unit) 46. The second gas pressure adjusting unit 46 includes,for example, a compressor for feeding the compressed air, a pump forsuctioning air, and the like. As a result, the internal pressure of thecylinder space S formed in the knockout cylinder 44 is controlled by thesecond gas pressure adjusting unit 46 via the gas valve (pistondisplacing unit) 56.

The gas valve (piston displacing unit) 56 causes the second gas pressureadjusting unit (gas pressure adjusting unit) 46 and the cylinder space Sof the knockout cylinder 44 (gas pressure adjusting unit) to communicatewith each other via the opening 54 formed in the table main body (base)23A of the turntable 23. Therefore, the gas pressure of the cylinderspace S is enhanced by the operation of the second gas pressureadjusting unit 46, or the internal air is suctioned.

For example, when the compressed air is supplied from the second gaspressure adjusting unit (gas pressure adjusting unit) 46, the gaspressure is applied to the cylinder space S of the knockout cylinder 44from the gas valve (piston displacing unit) 56 via the opening 54 of thetable main body (base) 23A. Thus, for example, when the knocking outpiston 45 is at the recessed position (see FIG. 7), the knocking outpiston 45 movably supported by the knockout cylinder 44 is displaced tothe protruding position (see FIG. 8) by the rise in the internalpressure of the cylinder space S.

Further, for example, when the suction is performed by the second gaspressure adjusting unit (gas pressure adjusting unit) 46, the cylinderspace S of the knockout cylinder 44 is suctioned from the gas valve(piston displacing unit) 56 via the opening 54 of the table main body(base) 23A. Accordingly, when the knocking out piston 45 is at theprotruding position (see FIG. 8), the knocking out piston 45 movablysupported by the knockout cylinder 44 is displaced to the recessedposition (see FIG. 7) by depressurization of the cylinder space S.

A predetermined gap is formed in the spacer plate 55 in a region of thefixed support plate 57 other than the position at which the gas valve(piston displacing unit) 56 is attached, and the interior of thecylinder space S is set to the atmospheric pressure state via theopening 55 a of the spacer plate 55 and the opening 54 of the table mainbody (base) 23A.

The operation of the can forming machine 20 of the present embodimenthaving the above configuration will be described.

When the opening side of the can body W3 (see FIG. 2E) formed in theprevious step is drawn, for example, by the can forming machine (neckingapparatus) 20 to form the can body 10 (see FIG. 2F) having the neck part12, for example, the can body with the bottom portion drawn in theprevious process is inserted into the recess 32 of the can body holder31 at the can body insertion position P1 (see FIG. 6).

When the can body is inserted, the can body holder 31 at the can bodyinsertion position P1 enters the recessed position at which the cylinderspace S of the knockout cylinder 44 is suctioned by the second gaspressure adjusting unit 46, and thus, the knocking out piston 45 exitsthe interior of the recess 32. The elastic part 42 constituting the canbody holding unit 33 enters a state in which no gas pressure is appliedfrom the first gas pressure adjusting unit 43, and is located at the canbody release position at which the elastic part 42 does not protrudefrom the inner circumferential surface 32 a of the recess 32 (see FIG.11A).

Further, when the can body 10 is inserted into the recess 32 of the canbody holder 31, the gas pressure is applied from the first gas pressureadjusting unit 43 to the inside of the hollow portion 42 a of theelastic part 42, and the gas pressure inside the hollow portion 42 a ofthe elastic part 42 increases. As a result, a portion of the elasticpart 42 exposed to the inner circumferential surface 32 a of the recess32 protrudes (bulges) from the inner circumferential surface 32 a.Further, the can body holding unit 33 at the can body release positionis displaced to a can body holding position (see FIG. 11B) at which theelastic part 42 narrows the diameter of the inner circumferentialsurface 32 a of the recess 32. As a result, the circumferential surfaceof the can body W3 introduced into the recess 32 is clamped by theprotruding portion 42 b of the elastic part 42.

Before insertion of the can body W3, the cylinder space S of theknockout cylinder 44 is suctioned in advance by the second gas pressureadjusting unit 46, for example, a suction pump. As a result, theknocking out piston 45 is brought to the recessed position at which itexits the recess 32.

Further, the knocking out piston 45 is located at the protrudingposition at the can body discharge position P2 before reaching the canbody insertion position P1, and in a state in which the knocking outpiston 45 is located at the protruding position, the knocking out piston45 can also be pushed into the recessed position by a pressing forcesuch as oil pressure for inserting the can body W3 into the can bodyholder 31 at the can body insertion position P1. In this case, it ispossible to omit the suction function from the second gas pressureadjusting unit 46. When the knocking out piston 45 is configured to bepushed into the recessed position by the pressing force for pushing thecan body W3 into the can body holder 31, at the can body insertionposition P1, the interior of the cylinder space S may be released to theatmosphere.

Thereafter, by the intermittent rotation of the turntable 23, theopening end side of the can body 10 supported by the can body holder 31is successively pressed against the forming toolings 41, 41 . . .annularly arranged on the die table 24 and is drawn in steps. As aresult, while the turntable 23 rotates once, the neck portion 12 (seeFIG. 2F) is formed in the can body 10.

During the machining of the can body W3 using the forming toolings 41,41 . . . and the screw tool 61 (before the can body holder 31 reachesthe can body discharge position P2 from the can body insertion positionP1), the can body 10 introduced into the recess 32 of the can bodyholding unit 33 is held (locked) on the circumferential surface of thebottom portion by the elastic part 42 of the can body holding unit 33.

Further, during machining of the can body W3 using the forming toolings41, 41 . . . and the screw tool 61, the gas valve (piston displacingunit) 56 connected to the second gas pressure adjusting unit 46 forchanging the internal pressure in the cylinder space S is not disposedin the opening 54 formed in the table main body (base) 23A which exposesthe rear end side of the knockout cylinder 44 to the outside.Accordingly, it is possible to prevent a problem in which the internalpressure of the cylinder space S increases due to air leakage or thelike, the knocking out piston 45 protrudes at an unexpected timing, andthe can body being machined falls.

When the can body holder 31 for holding the can body 10 in which themachining of the neck portion 12 using the series of forming toolings41, 41 . . . and the screw tool 61 or the formation of the thread groove13 is completed reaches the can body discharge position P2, the can bodyholding unit 33 stops application of the gas pressure from the first gaspressure adjusting unit 43 (see FIG. 7) toward the elastic part 42. Thecontrol of the gas pressure applied to the elastic part 42 is performedby a change in the relative rotational position between the sliding ringmember 25 and the fixing ring member 26. Because a state in which thegas pressure is not applied to the elastic part 42 is set, the elasticpart 42 returns to the original shape that does not protrude from theinner circumferential surface 32 a of the recess 32, and is displaced tothe can release position at which the can body 10 is not clamped (seeFIG. 11A).

Further, the gas pressure is applied from the second gas pressureadjusting unit (gas pressure adjusting unit) 46 to the inside of thecylinder space S of the knockout cylinder 44 via the gas valve (pistondisplacing unit) 56. Therefore, for example, when the knocking outpiston 45 is at the recessed position (see FIG. 7), the knocking outpiston 45 movably supported by the knockout cylinder 44 is displaced tothe protruding position (see FIG. 8) by the rise in the internalpressure of the cylinder space S.

As a result, the machined can body 10 is discharged from the recess 32of the can body holder 31 and is sent to the next process.

After the can body 10 is discharged from the can body holder 31, at anyposition of the can body insertion position P1 from the can bodydischarge position P2, the interior of the cylinder space S of theknockout cylinder 44 is suctioned from the second gas pressure adjustingunit (gas pressure adjusting unit) 46 via a gas valve (piston displacingunit) 56. As a result, the knocking out piston 45 movably supported bythe knockout cylinder 44 is displaced to the recessed position (see FIG.7) by depression of the cylinder space S.

As described above, in the can forming machine 20 of the presentembodiment, the gas valve (piston displacing unit) 56 for operating theknocking out piston 45 is provided only between the position at whichthe can body is discharged from the can body holder 31 and the insertingposition of the can body. Accordingly, it is possible to reliablyprevent an erroneous operation in which the knocking out piston 45unexpectedly protrudes into the recess 32 during machining of the canbody and causes the can body being machined to fall.

Although embodiments of the present invention have been described above,these embodiments have been presented as examples and are not intendedto limit the scope of the invention. These embodiments can be providedin various other forms, and various omissions, substitutions, andchanges can be made within a scope that does not depart from the gist ofthe invention. These embodiments and modifications thereof are includedin the scope and gist of the invention, and are included in theinvention described in the claims and the equivalent scope thereof.

For example, in the aforementioned embodiment, the knocking out pistonis operated by increasing or suctioning the gas pressure in the cylinderspace. However, in addition, for example, the knocking out piston may beoperated directly by a mechanical operating device such as a cam unit ora spring unit.

Further, for example, in the above-described embodiment, as theplurality of forming toolings 41 arranged in the die table 24, anexample of a die for forming a neck portion constricted on the openingend side of the can body is adopted. However, the forming tooling is notlimited thereto, and a die that gives an arbitrary shape to the can bodymay be adopted. Further, it is possible to dispose an optional can bodymachining unit such as a screw machining unit for attaching a bottlecap.

While preferred embodiments of the invention have been described andillustrated above, it should be understood that these are exemplary ofthe invention and are not to be considered as limiting. Additions,omissions, substitutions, and other modifications can be made withoutdeparting from the spirit or scope of the present invention.Accordingly, the invention is not to be considered as being limited bythe foregoing description, and is only limited by the scope of theappended claims.

REFERENCE SIGNS LIST

-   -   10: Can body    -   20: Can forming machine (Necking work apparatus)    -   21: Main body    -   23: Turntable    -   24: Die table    -   31: Can body holder    -   32: Recess    -   33: Can body holding unit    -   34: Knockout unit    -   41: Tooling    -   42: Elastic part    -   43: First gas pressure adjusting unit    -   44: Knockout cylinder (cylinder)    -   45: Knocking out piston    -   46: Second gas pressure adjusting unit    -   56: Gas valve (piston displacing unit)    -   57: Fixed support plate

What is claimed is:
 1. A can forming machine comprising: a turntable inwhich a plurality of can body holders configured to detachably hold acan body are annularly arranged on one surface side of a base in a discshape, wherein the can body holders have a recess into which a bottomside of the can body can be inserted, and a knockout unit, the knockoutunit has a knocking out piston which is disposed to be movable in adepth direction of the recess and is provided to be displaceable betweena protruding position at which the knocking out piston protrudes intothe recess and an recessed position at which the knocking out pistonexits the recess, and a cylinder which supports the knocking out pistonto be displaceable, and at a discharge position at which the formed canbody is discharged from the recess of the can body holders, a pistondisplacing unit which displaces the knocking out piston from therecessed position toward the protruding position is provided adjacent tothe other surface side of the base.
 2. The can forming machine accordingto claim 1, wherein an opening through which one surface side and theother surface side of the base communicate with each other is formed ina part of the base in which the can body holders are disposed.
 3. Thecan forming machine according to claim 1, wherein the piston displacingunit is a gas valve connected to a gas pressure adjusting unit whichfeeds gas into the cylinder.
 4. The can forming machine according toclaim 2, wherein the piston displacing unit is a gas valve connected toa gas pressure adjusting unit which feeds gas into the cylinder.
 5. Thecan forming machine according to claim 3, wherein the gas valve isfurther disposed to one or more positions between a position subsequentto the discharge position to an introduction position along a rotationaldirection of the turntable, and is not disposed between the positionsubsequent to the introduction position and a position previous to thedischarge position.
 6. The can forming machine according to claim 4,wherein the gas valve is further disposed to one or more positionsbetween a position subsequent to the discharge position to anintroduction position along a rotational direction of the turntable, andis not disposed between the position subsequent to the introductionposition and a position previous to the discharge position.
 7. The canforming machine according to claim 3, wherein the gas valve is disposedto each position between the discharge position and an introductionposition at which the can body before forming is introduced into therecess, and the gas pressure adjusting unit feeds gas into the cylindervia the gas valve and suctions the interior of the cylinder to displacethe knocking out piston from the protruding position toward the recessedposition.
 8. The can forming machine according to claim 4, wherein thegas valve is disposed to each position between the discharge positionand an introduction position at which the can body before forming isintroduced into the recess, and the gas pressure adjusting unit feedsgas into the cylinder via the gas valve and suctions the interior of thecylinder to displace the knocking out piston from the protrudingposition toward the recessed position.
 9. The can forming machineaccording to claim 5, wherein the gas valve is disposed to each positionbetween the discharge position and an introduction position at which thecan body before forming is introduced into the recess, and the gaspressure adjusting unit feeds gas into the cylinder via the gas valveand suctions the interior of the cylinder to displace the knocking outpiston from the protruding position toward the recessed position. 10.The can forming machine according to claim 6, wherein the gas valve isdisposed to each position between the discharge position and anintroduction position at which the can body before forming is introducedinto the recess, and the gas pressure adjusting unit feeds gas into thecylinder via the gas valve and suctions the interior of the cylinder todisplace the knocking out piston from the protruding position toward therecessed position.
 11. A can body holder comprising: a recess whichreceives a lower portion of a can body; a can body holding unit disposedto an inner circumferential surface side of the recess; and a knockoutunit disposed to a bottom surface side of the recess, wherein the canbody holding unit comprises an elastic part partially exposed on theinner circumferential surface of the recess, and the knockout unitcomprises a knockout cylinder, and a knocking out piston supportedinside the knockout cylinder to be movable in an axis direction of theknockout cylinder.
 12. The can body holder according to claim 11,wherein the elastic part is in a ring shape having a rectangular crosssection, made of rubber, a hollow portion is formed in the rectangularcross section, and a first gas pressure adjusting unit configured toapply a gas pressure from outside to an inside of the hollow portion isconnected to the elastic part.
 13. The can body holder according toclaim 11, wherein a substantially cylindrical cylinder shape is formedin the knockout cylinder, a pressure adjusting hole is disposed to theknockout cylinder to release an air compressed in the knockout cylinderby movement of the knocking out piston.
 14. The can body holderaccording to claim 12, wherein a substantially cylindrical cylindershape is formed in the knockout cylinder, a pressure adjusting hole isdisposed to the knockout cylinder to release an air compressed in theknockout cylinder by movement of the knocking out piston.